The development of the human body; a manual of human embryology . ge, during which there is aslight ascent of the testes, so that they come to lie a littlehigher in the abdomen. This stage is, however, of shortduration, and is succeeded by the stage of the final de-scent, which is characterized by the elongation of the vagi-nal processes of the peritoneum into the substance of thescrotum (Fig. 209, A). Since the gubernaculum is at-tached to the bottom of the process, and since its growthhas again diminished, the testes gradually assume again THE DESCENT OF THE TESTES. 389 their inguinal positi
The development of the human body; a manual of human embryology . ge, during which there is aslight ascent of the testes, so that they come to lie a littlehigher in the abdomen. This stage is, however, of shortduration, and is succeeded by the stage of the final de-scent, which is characterized by the elongation of the vagi-nal processes of the peritoneum into the substance of thescrotum (Fig. 209, A). Since the gubernaculum is at-tached to the bottom of the process, and since its growthhas again diminished, the testes gradually assume again THE DESCENT OF THE TESTES. 389 their inguinal position, and are finally drawn down intothe scrotum, slipping down between the walls of the vagi-nal processes and the infundibuliform fascia, which, to-gether with the other layers composing the scrotal wall,are differentiated at about this time. The condition which is thus acquired persists for sometime after birth, the testicles being readily pushed up-ward into the abdominal cavity along the cavity by whichthey descended. Later, however, the size of the openings. Fig. 209.—Diagrams Illustrating the Descent op the , Inguinal ligament; m, muscular layer; s, skin and dartos of the scro-tum; t, testis; tv, tunica vaginalis; vd, vas deferens; vp, vaginal pro-cess of peritoneum.—{After Hertwig.) of the vaginal processes into the general peritoneal cavitybecomes greatly reduced, so that each process becomesconverted into an upper narrow neck and a lower sac-likecavity (Fig. 209, B), and, still later, the walls of the neckportion fuse and become converted into a solid cord, whilethe lower portion, wrapping itself around the testis, be-comes the tunica vaginalis (tv). By these changes thetestes become permanently located in the scrotum. Dur-ing their descent the testes are drawn downward out ofthe mesenteries, the mesorchia, in which they were origi- 390 THE DEVELOPMENT OF THE HUMAN BODY. nally enclosed, and these structures flatten out and dis-appear, and, since the remains
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